2001-2002 Yamaha 50HP F50Z/T50Z Ouboard 4-stroke engines service manual, Page 201Get this manual
ILOWRIRemoving the lower unit Drain the gear oilFor draining procedures, see Chapter 3, "Replacing the gear oil Set the gearshift to the neutral position, and place block of wood between the anti-cavitation plate and propeller to keep the propeller from turning, and then remove the propeller nut and propeller
Lower unit
862Y6015
WARNING862Y6020
Do not hold the propeller with your hands when loosening or tightening itBe sure to remove the battery leads from the batteries and the engine shut-off switchPut block of wood between the cavitation plate and propeller to keep the propeller from turning34Disconnect the speedometer hose